batt charge question

[dupsta]

Silly question. My onboard charger recharges my batteries for my trolling motor but also charges my cold cranking batt for my main 1985 evinrude outboard. If I didn’t charge that starting batt with my onboard charger would it get charged via running the motor? I know that cars have the ability to charge their starting batt with an alternator. I always assumed that I had to manually charge my starting batt. Right?

[marshmat]

If I didn’t charge that starting batt with my onboard charger would it get charged via running the motor?

Most outboards charge their own starting battery, the only two connections to this battery are the two cables from the motor. You generally only add an external charger while the battery is in winter storage or if it's dead.
edit- I presume this relates to the same setup you discuss in http://www.boatdesign.net/forums/sho...d.php?p=142028 , in which case your current 3-output charger should probably be used to charge the two batteries in the trolling bank and your new electronics battery.....

[Frosty]

Your motor charges the batt especially if its a power trim and tilt model . They generally charge quite well.

Your 2 threads would indicate that you are using more power than you can take with you. Thats your problem in a nut shell.

Why do you need the GPS running when your trolling. You will have to start turning some stuff off. It wont do any harm to restart the GPS and only takes a minute.

The alternative is have one of those whisper quiete 220 --110 v generators. Wighs less that 1 battery and you will have power to spare. Can even do toast and a cup of tea, not to mention flood lights--within reason.

[dupsta]

Thanks MarshMatt
Yes it is the power and trim model.
Looks like I don’t need to have one of the three charger outputs hooked up to the starting batt, glad I asked. The more I ask around having 4 batt for this exact issue is common.
The hummingbird GPS/Sonar fishing system needs to be on to monitor: depth, ground structure, temp, location, also monitors fish activity and has a few safety alarms as well. When you fish for 6-10 hours a day that can use up energy.
I think you are right when saying I need more power, but I dont think the issue is that I can't bring more? "More power than I can bring" It is around thirty five extra pounds, not an issue.
I like your alternative generator idea, but I still think a smaller 12v batt would be a better alternative.
Thanks for all the help guys.

[Frosty]

Before you dash off, I was thinking maybe solar panels as an alternative --not as good as the gen but shade too. A pair of decent ones might just keep up with your demands.

You'lle have to do without tea and toast though!!

Ahhh well fishing seems to have gotten a bit complicated.